Function lookup_cdev works similarly with lookup_bdev, we can get
a cdev instance by lookup_cdev with a parameter of dev name.
This function will be used in quotactl to get a cdev by a dev name.
Signed-off-by: Dongsheng Yang <yangds.fnst@xxxxxxxxxxxxxx>
---
fs/char_dev.c | 13 +++++++++++++
include/linux/fs.h | 2 ++
2 files changed, 15 insertions(+)
diff --git a/fs/char_dev.c b/fs/char_dev.c
index e818faa..12c1bd5 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -474,6 +474,18 @@ out:
return cdev;
}
+struct cdev *lookup_cdev(const char *pathname)
+{
+ struct cdev *cdev;
+ int error;
+
+ error = __lookup_dev(pathname, &cdev, NULL);
+ if (error)
+ return ERR_PTR(error);
+
+ return cdev;
+}
+
/**
* cdev_add() - add a char device to the system
* @p: the cdev structure for the device
@@ -596,6 +608,7 @@ void __init chrdev_init(void)
EXPORT_SYMBOL(register_chrdev_region);
EXPORT_SYMBOL(unregister_chrdev_region);
EXPORT_SYMBOL(alloc_chrdev_region);
+EXPORT_SYMBOL(lookup_cdev);
EXPORT_SYMBOL(cdev_init);
EXPORT_SYMBOL(cdev_alloc);
EXPORT_SYMBOL(cdev_del);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 5c7d789..860b235 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2308,6 +2308,8 @@ extern void __unregister_chrdev(unsigned int major, unsigned int baseminor,
unsigned int count, const char *name);
extern void unregister_chrdev_region(dev_t, unsigned);
extern void chrdev_show(struct seq_file *,off_t);
+extern struct cdev *lookup_cdev(const char *);
+
static inline int register_chrdev(unsigned int major, const char *name,
const struct file_operations *fops)
--
1.8.4.2
--
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